1. Field of the Invention
This invention relates to a floppy disk drive unit.
2. Description of the Prior Art
Floppy disk drive units for recoding and reproducing data on a floppy disk are known. In such a floppy disk drive unit has upper and lower magnetic heads pinching a recoding medium of a floppy disk. The height of the lower magnetic head on the base of the carriage is offset to make the top surface of the lower magnetic head slightly higher than the recording medium to provide stable reproduction.
Japanese utility model application provisional publication No. 6-52049 discloses a floppy disk drive unit including upper and lower magnetic heads having the same height with a protruding portion formed on a gimbal on the base of the carriage.
Japanese utility model application provisional publication No. 7-10851 also discloses a floppy disk drive unit including upper and lower magnetic heads having the same height with a protruding portion on a gimbal on the base of the carriage.
In the floppy disk drive units disclosed in both documents, upper and lower magnetic heads pinch a magnetic medium contained in a floppy disk cartridge for reproducing and recording. The lower magnetic head is mounted on a lower gimbal plate for controlling the orientation of the lower magnetic head through a protruding portion which is upwardly protruded to provide penetration to the magnetic medium for reading and recording without difference in the heights of the upper and lower magnetic heads for the penetration.
The penetration is such that the magnetic recording medium is reproduced and recorded with the center plane of the elastic magnetic recording medium slightly offset upwardly to provide stable reproducing and recording. In both prior arts, heights of the upper and lower magnetic heads are the same, so that the common magnetic heads can be used for lower cost.
The aim of the present invention is to provide a superior floppy disk drive unit.
According to the present invention, a first aspect of the present invention is a floppy disk drive unit comprising: floppy disk supporting means for rotatably supporting a recording medium disk in a floppy disk cartridge having a shutter for accessing said recording medium; a head carriage assembly which is movable in the radial direction of said recording medium disk including: a carriage and an upper arm having lower and upper magnetic heads at their tips, respectively, said upper arm and said carriage being symmetrically arranged with respect to the center plane of said floppy disk cartridge which is parallel to a rotating plane of said recording medium disk and pinching said recording medium disk with said lower and upper magnetic heads while said recoding medium disk is set on said floppy disk supporting means; and a mounting plate between said lower magnetic head and said carriage having a predetermined constant thickness and a predetermined width in the tangent direction of said floppy disk which is greater than that of the lower magnetic head and smaller than that of said shutter, wherein said upper and lower magnetic heads include common magnetic heads having the same height in a direction perpendicular to said rotating plane and said lower magnetic head is fixed on said carriage through said mounting plate which provides penetration of said lower magnetic head to said recording medium disk toward said upper magnetic head. The orientation of said lower magnetic head is fixed because of absence of the gimbal plate.
Preferably, said predetermined thickness is greater than the thickness of said shutter.
Preferably, said mounting plate comprises a punched thin plate.
Preferably, a surface of said mounting plate on which said carriage is fixed has a rough area including holes in said mounting plate and said head carriage assembly further includes an adhesive layer for adhering said rough area to said carriage.
Preferably, said upper arm further includes a gimbal plate and said upper magnetic head is fixed on said upper arm through said gimbal plate.
Preferably, said mounting plate has a through hole for positioning the lower magnetic head.